In well completions a liner is typically inserted in the drilled wellbore and cemented. Thereafter the integrity of the cementing needs to be tested and that is accomplished with a pressure test using a packer set above the liner top. To avoid damage to tools that may be later set in the liner, the top of the liner needs to have a relatively burr free internal surface. Typically, a mill is used to dress the liner top. It is advantageous to condition the mud above the liner and to do it with relatively high circulation rates. To accomplish that a tool with a lateral port has been used that can open, when needed to allow conditioning.
Typically, these ported tools involve a ported mandrel in a ported housing where the ports can be selectively put into alignment for flow and misalignment to close off flow. In the past the required relative movement to go between the open and closed positions has been accomplished with j-slot mechanisms that involve relative movement between a pin on one part and a slot on the other. Progress of the pin in the slot could be obtained by cycling pressure on and off that forced relative movement between a j-slot sleeve and a lug to advance the lug in a j-slot track or by mechanical movement of the pin or slot with the other held supported. For example a mandrel with a pin extending into a slot on a surrounding housing that is supported in the well could allow the mandrel to take several positions with respect to the surrounding housing. That relative movement could result in aligning or misaligning of ports. The limitations of such j-slot mechanisms are that the pin continues to progress in the slot if there is reciprocating movement of the tool for other purposes. In that case if aligned ports were needed to stay aligned during reciprocating tool movement for another purpose such as conditioning the mud through a lateral port while reciprocating the tool the length of tubulars that can be assembled on a rig floor, for example about 90 feet, the j-slot mechanisms would not assure that the aligned ports would not go to a misaligned position and thus nullify the mud conditioning effort that was in progress. Thus, one advantage of the present invention allows the lateral port to remain open for conditioning by having a barrier to the progress of the lug out of a desired slot in the j-slot while mud is conditioned above a liner top.
Tools in the past have included bearings so that when weight was set down on the bearing the mandrel could rotate with ports in the mandrel selectively aligned with ports in the housing, as long as weight was set down. This rotation of the mandrel feature allowed better agitation of the mud as different outlets around the circumference of the outer housing saw flow in turn as the mandrel rotated. The problem was that if the tool was moved longitudinally back and forth from the position it took to align the ports such as if the span of the conditioning zone was 90 feet, for example, the j-slot device would cycle and the ports may no longer stay aligned.
What was needed in a cleanup and test tool of this type is an ability to open the lateral ports and hold them open while the tool is cycled up and down for a long distance and then later be able to close them. Another desirable feature was to be able to later still open the ports and circulate and swivel before pulling the tool out of the hole. These and other features of the present tool and associated method of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description and the associated drawings and the claims below that define the full scope of the invention.